How to interpret X2D Shadow Improvement Chart

[xoda]

I'm having a bit of trouble interpreting / understanding the shadow improvement chart for the X2D. My understanding is that all the values are relative to the base ISO of the camera. E.g. for the X1D, the improvement at base ISO 100 is 0, because that's basically comparing it to itself.

https://www.photonstophotos.net/Charts/PDR_Shadow.htm



But for the X2D chart, there is no "0". Even at ISO 64, which should be the lowest native ISO, it has a reading of 0.52 stops. At ISO 100, it's 0.33. So what the the ISO value to which 64 and 100 are being compared?

[MGrayson]

I have no idea. It looks like a simple bug. Or else I have no idea what they're really displaying. Or there is a secret ISO 25 mode. 

[SrMi]

I have contacted Bill about the graph and he has fixed it.

[xoda]

Th

I have contacted Bill about the graph and he has fixed it.

Thanks!